As many as seven first-team players could be unavailable for selection on Saturday, with several squad members likely to return next weekend for the Gunners' game against QPR
Koscielny misses out with a back injury, whilst Walcott remains sidelined with a chest injury after being on the receiving end of a dangerous tackle during England's 5-0 win over San Marino.
"Theo is out for Saturday, for sure. He has an injury to his chest and lungs. We have to treat that clinically. He's quickly short of breath when he makes an effort but it's bruising and that will heal," Wenger said.
"It's no major concern but it will take we think about two weeks to be back to a normal level.
Wenger also revealed that Gunners trio Kieran Gibbs, Wojciech Szczesny and Lukasz Fabianski are still recovering, and won't feature on Saturday.
"Gibbs is out for Saturday because he went off against West Ham. He's not healed yet. He has a little chance to be ready for Wednesday and a bigger chance for QPR," he added.
"Fabianski sees a specialist today [Thursday]. I don't know what will come out of that. It's an ankle ligament problem - a new problem. He was back in training before that. Szczesny I think is two weeks away."